How to remove button border after showing content?

Question

JavaScript

Good afternoon. There is a block with a Load More button. The button works well. But after showing the content, there is such a border from the button. How to remove it? Tell me please. Implemented in jquery. I'm not familiar with jquery.
here is the code

function closeNav() {
    document.getElementById("mySidenav").style.width = "0";
}
$(document).ready(function(){
  $("#loadMore").on("click", function(e){
    e.preventDefault();
    $(".content:hidden").slice(0, 4).slideDown();
    if($(".content:hidden").length === 0) {
      $("#loadMore").text("").addClass("noContent");
    }
  });
  
});

button before showing content

and button after showing content